Copper is a strange material. In its annealed form (heated to a dull red and cooled slowly) it is extremely ductile, and can be bent pretty much how you like, but just the once. After that, it 'work hardens' with each successive bend making it harder and less ductile, until it becomes almost brittle, and breaks easily if bent. The only way to make it ductile again is to heat it to dull red and slowly cool, which can be somewhat difficult if it is covered in PVC insulation.
I play around with copper pipes as well as wires, and have made thousands of bends in 15mm and 22mm tube. The correct wat to do this is to start with Table X copper tube, which is annealed to the correct degree, then to bend it slightly more than you require, before straightening it back to the angle you wanted. This is to leave the tube in a less stressed state than it would be after the initial bend.
Similarly with the main tails when the nice neat ends are no longer nice and neat once you get that last bend into it.
